Engine postprocessor inlet temperature optimization and oil consumption reduction method and device

The invention discloses an engine postprocessor inlet temperature optimization and oil consumption reduction method and device, a 48v system and a storage medium. The method comprises the steps that under the condition that an engine is controlled to operate in a thermal management mode, the inlet temperature of an engine emission postprocessor is monitored in real time; whether the inlet temperature of the engine emission postprocessor is smaller than the minimum working temperature of the engine emission postprocessor when the whole vehicle exhaust emission requirement is met or not is judged, if yes, the engine is controlled to quit the non-thermal management mode and enter the thermal management mode to operate, and meanwhile a BRM motor is controlled to execute the engine reverse dragging function; the inlet temperature of the engine emission postprocessor is increased by increasing the working load of the engine, so that the inlet temperature of the engine emission postprocessor is larger than or equal